Aircraft structure



Patented Aug. 14, 1945 Amcnm s'rnuc'rnnn Michael Watter, Philadelphia, Pa., assigner to Edward G. Budd Manufacturing Company, Philadelphia, Pa., a corporation of Pennsylvania Application September 14, 1942, Serial No. 458,251

(Ci. 24d- 123) 15 Claims.

This invention relates to alrfoil structures and more particularly to the formation of the skin blanket assembly and to means for attaching the same to chord-wise extending ribs. 'I'his application is a continuation-impart of my pendingapplication, 1941. Y p,

It is an object of the present-invention to provide a novel reinforcing structure for skin sheets and one in which the same is so formed thatit may be easily secured to the rib structure of the airfoil by a welding operation.

It is another object ofthe invention to provide a novel attaching clip so formed as to be readily attachable to the skin supporting structure and allowed to project intoface to face relationship with a side face of a rib for securement thereto.

It is still another Object of the invention to provide an attaching clip for skin blanket assem- 4 blies which is particularly adapted for attachment to S-shaped cap strips, forming a part of the rib assemblies.

According to the present invention, there is provided a series of channel members serving to support the skin sheet and having inwardly extending flanges or face portions.

sheet. Adapted to be disposed between adjacent flanges of two adjacent channel members for securement thereto is a strengthening stringer of tubular shape. For the attachment of this skin blanket assembly to a rib structure, there is provided attaching clips adapted to be attached to the inwardly extending flanges and adapted to extend into face to face engagement with a side face or cap strip of the rib assembly. The welding f the skin blanket assembly t0 the rib is thusK Serial No. 385,235, March 26,v

The channel members and their flanges, run spanwise of the skin made by the welding together of the face portions taching clip which is particularly adapted for the attachment of a skin blanket assembly to an following detailed description taken in connection with the accompanying drawings in which:

Figure l is a cross sectional View of the forward portion of an airfoll structure, showing a rib, 'skin blanket, and leading edge assemblies 'Ind theirl attachment to the rib;

Fig. 2 is a cross sectional view of the airfoil structure taken at the same station as that of Fig. 1 but of the rearward portion ofthe airfoil structure;

Fig. 3 is a fragmentary view in section of the skin blanket and rib assemblyshowing the atcuring the same to the tlrst form of skin blankety assembly and a modified cap strip;

Fig. V8 is a perspective View similar toFig. 4

of the modified form of skin supportingstructure with the modified form of attaching clip;

' Figs. 9 and 10 are perspective views taken from different angles of the modified attaching clip alone.

Referring now particularly to Figs. 1 and 2 there is shown generally, a leading edge assembly I l, top and bottom skin blanket assemblies l2 and l2', a chord-wlse extending rib I3, a spar structure Il and a trailing edge assembly l5.

The leading edge assembly |.I is composed of a nose forming rib Il and a skin sheet I1 reinforced with a series of spanwise extending. hat-shaped elements Il. Connected to the rearward edge of the skin sheet Il and to the noseformingrib Il thereof is a spanwise extending attaching portion Il and an attaching piece I! for the rib assembly Il. I

The skin blanket assemblies l2 and l2', include I a skin sheet 20 and a supporting structure oi channel-shaped reinforcing elements 2l arranged S-shaped cap strip, and one adapted to be connected to two opposed faces of the cap strip.

For other objects and fora. better understanding'of the invention, reference may be had to thel u to support the skin sheet 2U. the same being connected thereto as indicated by welding at 22. lach of these channel-shaped elements has inwardly extending flange portions 2l. Disposed between adjacent flange Portions of adjacent channel-shaped members are radially extending portions Il of tubular stringere Il. Formed on the flange portions 23 are seats 26 adapted to receive the tubular part of the stringers. These tubular stringers extend spanwise of the skin blanket and serve to reinforce considerably and form a part of the skin blanket supporting structure.

Referring now also to Figs. 3 vand 5 there will be noted the formation of attaching clips 21 which are utilized for the securing of the skin blanket assembly to a side face portionA 28 of a cap strip 29 forming a part of the rib assembly I3. 'I'hese attaching clips 21 having a transversely extending attaching portion 30 adapted to fit against one of the flanges 23 for securement thereto by the Welds 3i. These attaching clips are preferably welded to the skin blanket assembly prior to the skin blanket assembly being attached to the rib assemblies. The attaching portion 30 lies above an arcuate portion 32 formed to fit about the tubular stringers 25 and to serve as a seat for the same. This arcuate portion 32 is of flange-shape and runs with the stringer and parallel to the reinforcing edge pr tion 33 both of which give to the attaching clip, which is of sheet metal, added strength and rigidity. Adapted to extend below and into face to face engagement with the side face 28 of the cap strip 29 is an attaching portion 34. When the skin blanket assembly I2 is put in place and the rib structure I3 is brought into its proper with the spanwise extending attaching strip I8 of the leading edge assembly, as indicated at I8'. On the other side there is a similar connection with an inserted ange piece.

In the attachment of the attaching clip 21 by means of its transversely extending portion 30 to the ange 23 of a channel-shaped member, it will be noted that the same is performed by the same welding operation that the ange portions 23 are welded to the radially extending portions of the tubular Stringer 25. This common welding means is indicated at 3l. It should be apparent that the lower skin blanket assembly I2' is of similar construction as that of the skin blanket assembly I3 and that the same is 'similarly' attached to the rib assembly I3 and tothe leading edge asesmbly II. y

Referring now to Fig. 4 there will be noted a modified form of skin supporting structure for supporting the skin sheet 20.*of askin blanket assembly I2 or I2. The skin supporting structure includes a series of spaced reinforcing elements 40, each of which is formed of sheet material folded back against itself to leave a tubular or hollow portion at its apex 4I and flared at its open end to provide laterally spaced attaching flanges 42 and 43. These reinforcing elements are attached to the skin sheet by means of their iianges 42 and 43 as by welding as indicated at 44. The tubular or hollow portion 4I is of similar dimension as that of the tubular stringers in the form of the invention just described about which cai. be attached the regular attaching clip 21. The attaching portion 1 0 for thel clip 21 is welded to the reinforcing elements 40 bythe same welding that retains the 'sheet material which forms the same in its folded back formation. This welding means is indicated at 45.

Corning now to a modified form 41 of attaching clip which is particularly adapted for use in the connecting of the skin blanket assembly to cap strips of S-shape, it will be noted particularly in Figs. 9 and 10 that the attaching clip is formed with the additional anges or attaching portions 48 and 49.' It will Ialso be noted that the attaching clip 41 itself is of greater length than the attaching clip 21. With this additional length it will be seen the attaching portion 48 can seat against the inner face of the skin-supporting elements for attachment of the clip directly tothe skin sheet through merely the thickness of the skin-supporting elements. This is done by the welding as indicated at 50. This attachment of the portion 48 is made as well as the attachment of a portion 5I, corresponding to the attaching portion 30 of the attaching clip 21, which is welded to the reinforcing elements at a location inwardly of their connection with the skin sheet proper.

The attaching portion 49 is to provide an additional face on the attaching clip for connection with an opposite face 52 of an S-shaped cap strip 53. A connection is also made of an attaching portion 54, corresponding to the attaching portion 34 of the attaching clip 21, with a main face 53 of the cap strip 52. Figs. 6 and 8 show the connection'of a modified form of the attaching clip made in connection with the modifiedforrn of skin-reinforcing structure whereas Fig. '7- shows the modified attaching clip connected to the form of reinforcing structure shown in Figs. 1, 2 and 3.

It should now be apparent that there has been provided a skin blanket assembly including a skin sheet with a supporting structure which is so formed that the same can be readily attached to a rib structure merely by the use of pressed metal attaching clips, and these clips being so formed as to withstand and to transmit the load from the skin blanket assembly to the rib assembly forming a part of the frame of the airioill structure.

While various changes may be made in the detailed construction of the arrangement and of the attaching clip serving for the connection of the skin blanket assembly to the rib assembly,

.it shall be understood thatA such changes are Within the spirit and scope of the present linvention as defined by the appended claims.

What is claimed is:

1. In an airfoil structure, a plurality of spaced chordwise extending ribs, a skin blanket embodying a skin sheet and a plurality of spanwise extending stringers secured to said skin sheet, the skin blanket being disposed entirely above the ribs, a plurality of attaching portions extending from said stringers in lapped relation with vertical side faces of said ribs, and means for securing said attaching portions to said ribs through said side faces, the stringers having their lowermost parts disposed in a surface located at a distance from a parallel surface defining the uppermost adjacent parts of the ribs so that the attaching portions ferm strut-like connections between the stringers and ribs. whereby the skin blanket may be shifted longitudinally along the length of the yribs or transversely along the width l of the ribs to take up an adjusted position in making connection between the'skin blanket and the assalito ribs. and whereby the attachingmeans are substringers and secured to the vertical sides of said ribs, the stringers having their lowermost parts disposed in a surface located at a distance from s, parallel surface defining the uppermost adjacent parts of the ribs so that the attaching members form strut-like connections between the stringere and ribs, whereby the skin blanket may be shifted longitudinally along the length of the ribs or transversely along the width of the ribs to take up an adjusted Iposition. in making connection between the skin blanket and the ribs, and whereby the attaching members are subjected to load during flight.

3. In an airfoil structure, a plurality of chordwise extending ribs, a skin blanket embodying a skin sheet and a plurality of spanwise extending. parallel stringere having a portion of tubular shape in cross-section, said stringers being of thin gauge sheet metal, the skin blanket standing clear above said ribs and having no direct connection thereto, and means for securing the skin blanket to said ribs comprising a plurality of metal members each secured 'to one side only and projecting from said stringere and means for rigidly securing said metal members metal members' having an arcuate seat portion drmly engaging the Stringer to which it is attached, the stringere having their lowermost parts disposed in a surface located at a distance from a parallel surface defining the uppermostv adjacent parts of the ribs so that the attaching members form strut-like connections -between the stringere and ribs, whereby the skin blanket may be shifted longitudinally along the length of the ribs or transversely along the width of the ribs to take up an adjusted position in making connection between the skin blanket and the ribs, and whereby the attaching members are subjected to load during night.

4. In an alrioil structure, a reinforced skin blanket comprising a thin gauge metal skin sheet. a plurality of reinforcing channels having their bases secured to said skin sheet, adjoining channels having their adjacent side portions in closely spaced parallel relation, and tubular strlngers of thin gauge sheet metalhaving radially extending portions disposed between the closely spaced to said ribs, each of saidvergent relation toward the skin sheet and terminating in opposed nanges secured .to said skin sheet, and a plurality of blanket attaching members secured to said elements at points of attachment to a supporting frame.

7. In an airfoil structure, a chordwise extending rib, a skin blanket assembly including a skin sheet, a plurality of channel-shaped stringer members for supporting the skin sheet and having inwardly extending portions, adjacent inwardly extending portions of the respective channels being secured together to Iprovide spanwise extendlng stringer portions, attaching clips secured to the stringe-r portions and adapted to extend into engagement with the chordwise extending rib, and means for securing the attaching clips to the ribs, the Stringer members having their lowermost parts vdisposed in a surface located at a distance from a parallel surface dening the uppermost adjacent parts of the ribs so that the attaching clips form strut-like connections between the Stringer members and ribs, whereby the skin blanket may be shifted longitudinally along the length of the ribs or transversely along the width of the ribs to take up an adjusted position in making connection between the skin blanket and the ribs, and whereby the attaching clips are suhject to load during flight. l 8. In a airfoil structure, a chordwise extending rib, a skin blanket assembly including a. skin sheet, a plurality of channel-shaped members.

for supporting the skin' sheet and running spanwise thereof, each of said channel-shaped members having inwardly extending nan'ges, the

channel-shaped members arranged with a Hangs' of one adjacent to a ange of another, strengthening Stringer elements having portions adapted to be disposed between adjacent flanges. attaching clips for securing the skin blanket assembly to the rib, said clips having portions positioned alongside said ilanges, and means for securing together adjacent flanges, strengthe stringer element portions, and the attaching clips.

9. In an ali-foil structure, a. chordwise extending rib, a reinforced skin blanket assembly infcluding a skin sheet, a plurality of spanwlse olttending reinforcing elements formed or sheet metal, said elements including a. tubular. portion having abutting radial liange portions secured together' adjacent the tubular portion and portions extending in divergent relation toward the l skin sheet and terminating in oppositely disposed Ult channel side portions and securely welded thereto. l

5. In an airfoll structure, a reinforced skin blanket comprising a thin gauge metal skin sheet,

6. In an airfoil structure.l a reinforced skin blanket comprising a thin gauge metal skin sheet.

a plurality of reinforcingv elements each formed of thin sauge sheet metal. each ot said elements comprising a'- tubular portion having abutting radial flange portions welded together .adjacent the tubular portion thereof and extending in dianges secured to said skin sheet, attaching clips for securing the skin blanket assembly to the chordwise extending rib, said attaching clips being shaped to lit about the tubular portion and having an attaching portion for securexrlent ci the clip to the reinforcing element in the region in which the abutting radial flange portions are secured together.

10. In an airfoil structure, a chordwise extending rib, a reinforced skin blanket assembly including a thin gauge metal skin sheet and a plurality of lspanwise extending reinforcing elements formed of sheet metal, said elements iri- `cluding a tubular portion having abutting radial flange portions secured together adjacent the tubular portion thereof and portions extending in divergent relation toward the skin sheet and terminating in oppositely extending flanges secured to said skin sheet, attaching clipsfor securing the skin blanket assembly to the chord- Wise extending rib, said attaching clips being contoured to nt about one-half of a face of the reinforcing element and having attaching porextending reinforcing portions With 'faces extending normal of theblanket assembly, attaching clips for securing the skin.- blanket .'assemblyto the chordwise extending .rib,iand 'each of-'said attaching clips contoured tofit a faceltofthe spanwise extending reinforcing portions and 4having curement with the reinforcing portions at ailoil attaching portions projected respectively for secation inwardly removed from the sk insheet and also at thelocation ofsecurement ofthe reinforcing portions with the skin sheet;- the. skinv-`` reinforcing structurehavingits lowermost parts disposed. in, a surfacel located atradistance from a parallel surface defining .the uppermost adjacent parts of the ribsso thatthe attaching clips form strutflike connections between the skinfreinforcing structure andribs, whereby the 4.skin blanket may be shifted longitudinally along the length of the ribs or transversely along the width .of the ribs to take up an adjusted position in making-connection between the skin blanket and the ribs, and whereby the attaching clips are subjected to load during flight.

41 2. In an airfoil structure, a chordwise extending rib having a cap strip of a shape providing a hannel opentoward the outside at the rib attaching edge and with opposed side faces, a reinforced skin blanket assembly including a skin sheet; and having spanwise reinforcing portions y .masa-eso I tions for securing the same to :the-reinforcing `elements in therregionjofathefsecuringf of the portions and provided with means for securing the clips to the reinforcing portions at a location inwardly removed from the skin sheet and atza location adjacent to the securement of the reinforcing portions with the skin sheet, each of said attaching clips being further secured to the face of a reinforcing portion and having spaced attaching portions projected into the open channel of the cap strip and secured respectively with the opposed faces thereof.

14-In an .airfoil structure in combination, Stringer and rib elements disposed transversely of each Y 0ther;. a skin sheet secured to said stringer elements, said Stringer elements includin g. a.web portion extending away from the rib elements .and also including overhanging lateral portions adjacent the rib elements, and clips for ,securing Stringer elements to rib elements, each clip*` including a portion lying alongside and se- .eured to?. one face of the web portion of the stringer elementfa portion lying alongside and secured to ya vertical .side face of a. rib element, and a portion extending past ,said overhanging Stringer portion, al1-parts of said clip being disg5 posed on one side of said Stringer element, the

' Stringerv elements having -their lowermost parts disposed in a surface located at a distance from a parallel surface defining the uppermost adjacent parts of the ribs so that the attaching clips form strut-like connections between the Stringer elements and ribs', whereby the skin sheet and its attached stringer elements may be shifted longitudinally along the length of the ribs or transversely, along the width of the ribs 35' to take up an adjustedl position in making conwith feces extending normal to the skin sheet,

Stringer and rib elements disposed .transversely attaching clips for securing the skin blanket assemblyto the chordwise extending rib, each of saidgattaching clips being secured to the face of a reinfomingportion and havingspaced attaching portions projected into the open channel of 4the cap strip and vsecured respectively with the op-V posed faces thereof.

l3, In an airfoil structure, a chordwise extending ribhaving a cap strip of a shape providing a channelopen toward the outside at the rib attaching edge and with opposedside faces, a

reinforced skin blanket assembly including a skin sheet and having spanwise reinforcing portigns with faces extending normal.' ,to the skin sheet, attaching clips for securing thev skin blanket assembly to the chordwise extendingfrib, f 5 each of said. attaching cnpsbemg qontouredfwf f spaced wall portions 0f the nt a face of'the spanwise extending'reinforcing y l nection between the stringer elements and ribs', and whereby the attaching clips are subjected to load during flight.l

l5. In an airfoil structure in combination,

of each other in different planes, l a skin sheet portion of the stringer element, a portion lying 

